One of the biggest problems with HVAC malfunctions is a dirty coil. Your air conditioner has an indoor evaporator coil and a condenser coil in the outdoor unit. The unit that rests outside of your home can easily become dirty because it is constantly exposed to the weather elements. Items that are common outside such as branches, dirt, grass clippings can make their way into the unit and affect the coils in the long run. Many components in your HVAC system are delicate so it is best to leave major cleaning to the professionals who are seasoned in HVAC maintenance like your HVAC technician.